Liquid fuel blowtorch with elastic air supply jacket



Feb. 3, 1953 v H. B. LANGE ETAL LIQUID FUEL BLOWTORCH WITH ELASTIC AIR SUPPLY JACKET Filed July 10, 1950 In M M G A I I NGR G l I ENH F 5 WAC H D ILL II, 8

IlIl YE l RN llllllllllllllllll I! llllllllll lllllllllal ATTO RNEYS Patentecl Feb. 3, 1953 LIQUID FUEL BLOWTORCH WITH ELASTIC AIR SUPPLY JACKET Harry B. Lange, Detroit, and Rodney E. Christian,

Dearborn, Mich., assignors to Kerr Manufacturing Company, Detroit, Mich., a corporation of Michigan Application July 10, 1950, Serial No. 172,906

2 Claims. 1

The invention relates to blow torches adapted for various uses, but more particularly designed for the localized heating of articles formed of thermo-plastic material such, for instance, as used in the practice of dentistry.

It is the object of the invention to obtain a construction that can be easily grasped by the hand of the user and operated to direct the flame against a particular point in the work.

It is a further object to obtain a construction with which the flame can be ejected or withdrawn substantially instantaneously.

Still further it is an object to obtain a relatively light article which can be used by the operator without fatigue.

With these objects in view the invention consists in the construction as hereinafter set forth.

In the drawings:

Fig. 1 is a side elevation of our improved blow torch;

Fig. 2 is a top plan view thereof;

Fig. 3 is an enlarged vertical central section.

With blow torches of the type as heretofore constructed, it has been usual to provide the torch proper, including fuel reservoir, wick and blow nozzle, with an external collapsible bulb for supplying the air. With our improved construction the essential elements are self-contained, being within or supported by a casing which may be easily grasped by the hand of the user. Furthermore, this casing is provided with resiliently flexible walls and has formed therewithin an air chamber from which air may be ejected as desired by the pressure of the grasping hand. Such pressure can be produced without changing the position of the structure as a whole, so that the flame may be accurately directed against the area to be heated.

More in detail, the outer casing A is preferably formed of a molded plastic material such, for instance, as a polyethylene which is flexible and highly resilient while still retaining sufficient rigidity to hold its shape when grasped by the hand. The casing is of generally cylindrical form having a contracted neck portion B also cylindrical, and with an external screw thread C for attachment of a cap. The cap D has a threaded portion D of molded plastic for engaging the thread C. Also an outer rigid shell D and a central portion D apertured for the passage of a wick therethrough. The wick E extends downwardly wtihin the casing A into contact with the fuel supply therein. This fuel supply is preferably carried by a separate container F, which is attached to the cap and extends downward through the neck 2 B centrally within the casing A. The container F, when removed, may be filled through the bottom end thereof which latter has a threaded bushing F, a screw plug F and a sealing gasket F The body of the container F is preferably formed of tubing, which at its upper end is secured to the portion D D is a portion extending upward from the portion D surrounding the wick and slightly contracted in diameter to hold the same. An extinguisher cap G fits over the portion D said extinguisher being attached to the cap portion D by a flexible resilient wire G which, when the cap is removed from the wick, will still retain it but out of the path of the flame. H is a small tube passing downward through an aperture in the cap portion D into communication with the air space between the container F and the neck B. The upper end of the tube H is closed but there is formed in the side adjacent to the wick a small aperture H forming a nozzle through which air may be blown against the flame. A sealing gasket I is placed within the cap D in contact with the upper end of the neck portion B, but the tube H extends within this gasket to communicate with the air space within the casing A as previously described. At some point in the casing or cap, and preferably as shown in the bottom of the casing thereof, there is provided an air entrance aperture in which is placed a check valve J. This check valve may be secured by a grommet K formed of flexible material such as rubber, which is engaged with an aperture in the bottom of the container A. The bottom portion is centrally raised to provide clearance for this grommet and the check valve.

With the construction as described when the casing A is grasped by the hand of the user, it may be carried about and held in position without collapsing the resilient walls. However, a little additional pressure will effect such collapsing and will blow air out through the tube H and aperture H laterally across the flame from the wick B so as to project the flame to the desired point. The bottom and top walls and also the neck of the casing are of greater thickness than the cylindrical side walls, so that the latter may be pressed inward without distorting the general shape of the structure.

What we claim as our invention is:

1. A blow torch comprising a hollow casing formed of molded resilient plastic material and of generally cylindrical form, said casing being of a diameter to be grasped by the hand of the user and having sufficient rigidity to hold this general form when thus grasped but being deformable by hand pressure to a greatly reduced volume, a neck of smaller diameter at the upper end of said casing, a cap engaging said neck and sealing the same and being formed with an aperture, a cylindrical liquid fuel container depending from said cap and insertable through said small diameter neck to extend downward within said casing to near the bottom thereof, a wick within said container extending outward through said aperture in said cap, a tube mounted on said cap at one side of said wick and extending inward through the cap into communication with the air space in said container, said tube being closed at its upper end and having a small aperture therein on the side adjacent to the flame of said wick, the bottom of said casing having an aperture therein, and a check valve mounted within said aperture permitting ingress of air.

2. The construction as in claim 1 in which the bottom and top portions of said casing including said neck are formed of greater thickness than the cylindrical side walls for greater rigidity, said ,neckv portion having external molded screw threads thereon and said cap having internal threads for engaging those of the neck, and an annular sealing gasket for engaging the top of the neck, said inner container being formed of tubing rigidly secured to the cap and having at its lower end a threaded bushing and a plug cap engaging the same to form a closure, said check valve having a resiliently flexible grommet securing the same within the aperture in the bottom portion.

' HARRY B. LANGE.

RODNEY E. CHRISTIAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 20 1,722,377 Kaplan July 30, 1929 1,722,378 Kaplan July 30, 1929 1,755,216 Hanau Apr. 22, 1930 

